Sourwood

Sourwood - Oxydendrum arboreum
Heath Family (Ericaceae)

 

Introduction: Truly a tree for all seasons, sourwood is one of our most beautiful natives and is ideal as a small specimen tree. It has lovely flowers that open in mid-summer, excellent fall color, and hanging racemes of fruit capsules in the winter. Sourwood offers some of the best fall color among trees in the South, and has the best red of any of our natives. Fall color ranges from red to purple to yellow, and all three colors are often on the same tree.
 
Culture: Sourwood is an exceptional tree for slightly acidic (pH 5.5-6.5), well-drained soils. It can be grown in full sun or partial shade although flowering and fall color are best in full sun. The tree does reasonably well in dry, neutral soils. Sourwood can be grown in Zones 5 (perhaps 4) to 9. This tree will not tolerate dry, compacted, alkaline soils or deicing salt, and is sensitive to root disturbance, so it is not ideal for urban areas. Sourwood has no serious pest problems. It should be transplanted as a young, balled-and-burlapped or container-grown plant.
 

 

Botanical Information
  • Native habitat: Coast of Virginia to North Carolina and in southwestern Pennsylvania, southern Ohio, Indiana, western Kentucky, Tennessee, the Appalachians to western Florida and the coasts of Mississippi and Louisiana.
  • Growth habit: A pyramidal growth habit with a rounded top and drooping branches.
  • Tree size: Reaches a height of 25 to 30 feet with a spread of 20 feet. Has a slow growth rate.
  • Flower and fruit: Small, quarter-inch flowers look like upside-down urns. They open in June and are fragrant, white, and hang from 4- to 10-inch panicles. The flowers persist as clusters of small brown fruit. Fruit is a dehiscent, five-valved capsule about one-third of an inch long.
  • Leaf: Alternate, simple leaves are 3 to 8 inches long and 1½ to 3½ inches wide. Leaves are dark green, slick and glossy, helping prevent injury from pollution.
  • Hardiness: Winter hardy to USDA Zone 5.

 

Additional information:
Sourwood's bark is grayish brown tinged with red, and deeply furrowed with scaly ridges. In the wild, its bark often looks blocky like that of persimmon. Planting sourwood next to black gum (Nyssa sylvatica) makes for a great fall color combination.

Sourwood makes an excellent specimen tree, and can also be used in shrub borders with Rhododendron, Pieris and Leucothoe. Sourwood's wood is hard and has red-tinged brown heartwood and thick layers of pale sapwood.

Lumber is used for tool handles and was once used to make wagon sled runners. Sourwood flowers are very attractive to bees, and sourwood honey is common in the South.

Its honey, which has a medium to light color with heavy body, is slow to granulate.

The scientific name for sourwood comes from the Greek words oxys (acid) and dendron (tree) and refers to the sour taste of its leaves. The leaves are used as a thirst-quencher by hikers and mountain climbers, and were once brewed to make a tonic.

The largest known sourwood in North America is in Robbinsville, N.C. It is 118 feet tall with a 2-foot trunk. Sourwood was introduced into the landscape in 1747.

 
 

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